Regeneron Pharmaceuticals Inc v Kymab Ltd

A product patent is sufficient only if its disclosure, combined with common general knowledge at the priority date, enables the skilled person to make substantially all products within every relevant claimed range without undue burden or inventive ingenuity. A range is relevant where its defining variable significantly affects the product’s value or utility for its intended purpose.

A general principle may support a broad claim where it is reasonably likely to enable the whole range to be made. It is insufficient that every product would obtain the invention’s benefit if and when later inventions made those products possible. De minimis failures and ranges defined by wholly irrelevant characteristics do not invalidate an otherwise sufficient claim.

Regeneron owned two patents concerning transgenic mice whose genomes contained a reverse chimeric locus. It alleged that Kymab’s transgenic mice infringed three claims. Henry Carr J found infringement but held the claims invalid for insufficiency because the patents did not enable the claimed subject matter to be performed.

The Court of Appeal, in [2018] EWCA Civ 671, found that the skilled team could make mice containing a small subset of human variable-region gene segments. It nevertheless upheld the claims across their full range because every claimed mouse would benefit from the invention’s solution to murine immunological sickness.

The central issue was whether a product claim is sufficient where the patent enables only some products in a relevant range to be made at the priority date, although all products would obtain the invention’s benefit if and when they became capable of being made.

1. Appeal allowed by a majority. Lord Briggs, with whom Lord Reed, Lord Hodge and Lord Sales agreed, held that the claims were invalid for insufficiency. Lady Black dissented and would have dismissed the appeal.

2. For a product claim, the patent bargain requires the monopoly to correspond to what the disclosure contributes to the art. That contribution is the skilled person’s ability to make the claimed product, rather than the inventive idea or the benefits which that idea may eventually confer. The disclosure may be supplemented by common general knowledge and reasonable experimentation, but it cannot require inventive ingenuity.

3. Under article 83 of the European Patent Convention and sections 14(3) and 72(1)(c) of the Patents Act 1977, the disclosure must enable the skilled person, at the priority date, to make substantially all types or embodiments within the scope of a product claim. A patentee may frame a broad claim but assumes the corresponding obligation to provide a sufficiently broad disclosure. De minimis failures do not necessarily invalidate a claim.

4. A patentee may rely on a principle of general application where it is reasonably likely to enable the whole claimed range to be made. The principle must make the claimed variants available without further inventive work. It is insufficient that the variants, once made through later inventions, would all enjoy the same beneficial effect.

5. Enablement is required only across a relevant range. A range is relevant when its defining variable significantly affects the product’s value or utility for its intended purpose. A wholly irrelevant characteristic, such as a mouse’s tail length, does not create a material enablement requirement.

6. The quantity of human variable-region material incorporated in the mice was a relevant variable because it was understood at the priority date to affect the diversity of useful antibodies produced. The patents enabled only mice containing a very small part of that region. Mice at the more valuable end of the claimed range required significant later inventions. The monopoly therefore extended substantially beyond the patents’ contribution to the art.

7. Lady Black considered that the reverse chimeric locus was properly characterised as a principle of general application. Every claimed mouse deployed that principle and obtained its solution to immunological sickness, irrespective of the quantity of human material incorporated. On that characterisation, she considered the full range sufficiently enabled.

1. United Kingdom Supreme Court: By a majority, allowed Kymab’s appeal and restored the conclusion that the relevant patent claims were invalid for insufficiency.

2. Court of Appeal: In [2018] EWCA Civ 671, reversed the finding of insufficiency. It held that the skilled team could make some claimed mice and that the reverse chimeric locus was a principle of general application whose benefit extended across the claim.

3. High Court: Henry Carr J found the relevant claims infringed but invalid for insufficiency because the patent did not enable the claimed subject matter to be performed without undue burden or invention.